Národní úložiště šedé literatury Nalezeno 4 záznamů.  Hledání trvalo 0.01 vteřin. 
Computer-assisted Search of the Roots of the Polynomial
Smetana, Bedřich
This article describes finding roots of polynomials, specifically aimed at finding real roots of a polynomial. Computer Support focuses on the use of generally available programs such as spreadsheets, portals to solve mathematical problems and freeware applications. Attention is devoted to a comparison of commercial and open source software.
STRUCTURAL, THERMODYNAMICS AND PHYSICAL PROPERTIES OF Zn Sn Al ALLOYS
Drápala, J. ; Musiol, J. ; Petlák, D. ; Vodárek, V. ; Smetana, B. ; Zlá, S. ; Kostiuková, G. ; Kroupa, Aleš ; Sidorov, V.E.
Some results of thermodynamic, structural and physical properties of Al-Sn-Zn alloys are presented in our paper. The ternary Al-Sn-Zn alloys were prepared in a resistance furnace in evacuated ampoules. The alloys were studied metallographically, their micro-hardness and X-ray micro-analysis (EDX, SEM) of individual phases were measured. Temperatures of phase transitions (liquidus, solidus, invariant reactions, etc.) were obtained using the DTA method (Setaram SETSYS 18 (TM)). The long time annealing (250, 300, 350 degrees C, 3, 7, 14 or 28 days) was used in order to achieve the thermodynamic equilibrium. The results were confronted with thermodynamic modelling of the ternary Al Sn Zn system in the Institute of Physics of Materials AS of the Czech Republic in Brno. We have studied density (by gamma-absorption method), electrical resistivity (by contactless method in rotating magnetic field) and magnetic susceptibility (by Faraday's method) of some Al-Sn-Zn alloys containing up to 10 at.% of aluminum and up to 65 at.% of zinc. The increasing of zinc content resulted in the decrease of the density and susceptibility values, except for one sample. The resistivity values practically didn't depend on the zinc content in the crystalline state, whereas a maximum was found for one of the samples in the liquid state. This work has been made in the frame of COST Action MP0602 project 'Advanced Solder Materials for High-Temperature Application'.
New types of lead-free solders and their properties
Drápala, J. ; Petlák, D. ; Malcharcziková, J. ; Vodárek, V. ; Konečná, K. ; Smetana, B. ; Zlá, S. ; Kostiuková, G. ; Seidlerová, J. ; Lasek, S. ; Madaj, M. ; Kroupa, Aleš ; Urbánek, J. ; Dušek, K. ; Sedláček, J. ; Sidorov, V.E.
Ternary and binary alloys with different ratios of Ag, Al, Bi, Cu, In, Mg, Sb, Sn and Zn were prepared experimentally. The following characteristics were studied: temperatures and enthalpies of phase transformations (DTA, TG, DSC), macro-and micro-structural analysis, micro-hardness, chemical analysis, X-ray and density measurements and electrical resistivity of selected solders, test of wettability with or without use of fluxes, measurement of corrosion properties.
Study of Zn-Sn-Al alloys for high-temperature solders
Drápala, J. ; Kroupa, Aleš ; Smetana, B. ; Burkovič, R. ; Lasek, S. ; Musiol, L.
The specimens were studied metallographically including the micro-hardness measurements, complete chemical analysis (ICP-AES, OES), X-ray micro-analysis of alloys by EDAX or WDX including SEM (BSE) in order to determine the composition and identification of individual phases.

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1 Smetana, Bedřich
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